chordates and tidsues

Reptilian Characteristics

  • Identity of Reptiles
    • First group of organisms to be truly terrestrial.
    • Born with lungs, unlike amphibians that use gills.
    • Body covering: scales.
    • Breeding in water but surfacing to breathe, e.g., sea turtles.

Sea Turtles

  • High Risks
    • All sea turtles are endangered.
    • Threats:
    • Egg harvesting.
    • Hunting for shells.
    • Entanglement in fishing gear, restricting breathing.
  • Lifespan and Reproduction
    • Long lifespan; reproduction begins around 10 years old.
    • High mortality rate when eggs hatch; successful ratio is low (1-2 to adulthood).
    • Predation is common for young turtles.
  • Diet
    • Primarily feed on jellyfish, but often mistake plastic for food.

General Characteristics of Reptiles

  • Examples of Reptiles:
    • Crocodiles
    • Alligators
    • Snakes
    • Lizards
    • Turtles
  • Physiology:
    • Ectothermic (cold-blooded); body temperature is regulated by the environment.
    • Physiological strategies for temperature management:
    • Sunbathing behavior to warm up.
  • Hibernation:
    • Some reptiles hibernate based on local climate; tropical reptiles do not.
    • Behavior changes in cooler temperatures; may slow down or reduce activity.

Amniotic Eggs in Reptiles

  • Unique Traits:
    • First seen in reptiles; a key evolutionary development.
    • Provides protection for the developing embryo; nutrient source is included.
    • Eliminates the need for water during development.
  • Shells:
    • Can be leathery or hard.
    • Require several weeks for embryo development.
  • Turtle Anatomy:
    • Turtles have a shell that is a part of their body.
    • Carapace (top shell) and plastron (underside shell).

Snake Physiology

  • Feeding Mechanism:
    • Able to unhinge jaws to ingest large prey.
    • Constriction is a common pre-kill strategy.
  • Venomous Species:
    • Venom is injected to subdue prey.

Evolutionary Stability of Reptiles

  • Reptiles have exhibited little evolutionary change for approximately 200 million years.
  • Adaptations:
    • Designed for reproductive success and survival in their environments.

Endothermic Organisms

  • Definition: Endothermic organisms maintain their body heat through metabolic processes, unlike ectothermic animals.
  • Physical Adaptations:
    • Birds exhibit adaptations allowing survival in diverse environments (e.g., polar and tropical regions).
  • Mechanisms:
    • Birds prevent overheating and have physiological responses to cold (e.g., torpor in hummingbirds).

Bird Characteristics

  • Innate Features:
    • Direct descendants of dinosaurs.
    • Adaptations like hollow bones for flight.
  • Waste Excretion:
    • Birds convert metabolic waste to uric acid; results in less fluid content and allows for lightweight excretion.
  • Reproductive Traits:
    • Lay amniotic eggs with microscopic pores for gas exchange.

Mammalian Characteristics

  • General Traits:
    • Covered in fur or hair at some life stage.
    • Feed young with milk (mammary glands).
    • Breathe with lungs and give birth to live young.
  • Teeth as Identification:
    • Serve as key identifying features among different mammal species.

Types of Mammals

  • Toothed and Baleen Whales:
    • Toothed whales have teeth, while baleen whales use baleen plates to capture food.
  • Evolutionary Context:
    • Mammals diversified significantly after the extinction of the dinosaurs.
  • Pregnancy and Reproduction:
    • Internal fertilization; all mammals are dioecious (distinct male and female).
    • Defined mating seasons correlate with environmental responsibilities.
  • Social Behaviors:
    • Vocalizations during mating season or parenting are common.

Animal Tissues Overview

  • Four Types of Tissues:
    • Epithelial Tissue:
    • Covers and protects external and internal surfaces.
    • Functions: protection, secretion, sensation, absorption.
    • Muscle Tissue:
    • Classified into three types:
      • Striated Muscle: voluntary movement, e.g., skeletal muscles.
      • Smooth Muscle: involuntary, e.g., walls of organs.
      • Cardiac Muscle: involuntary, heart muscle.
    • Nervous Tissue:
    • Composed of neurons; facilitates communication and response within the organism.
    • Connective Tissue:
    • Supports, binds other tissues; examples include blood, cartilage, fat.

Discussion on Animal Systems

  • Introduction to Animal Systems:
    • Discussing mechanisms of energy acquisition (e.g., digestion).
    • Introduction to various organ systems, focusing on multicellular organisms.
    • Practical anatomy will be combined in examples from various phyla.
  • Next Steps:
    • Transition into discussing animal organ systems in more detail.